1. Field of the Invention
The present invention relates to a nano-fabrication method, and more particularly, to an inorganic resist material and a nano-fabrication method by utilizing the same.
2. Description of Related Art
With the rapid development of 3C science and technology, it is necessary for the semiconductor process and information recording media process to reduce line width or the size of recording pit, so as to improve the operation speed and the recording density. Taking optical disc storage as an example, the length of the minimum recording pit of DVD discs is approximately 400 nm, and the length of the minimum recording pit of the next generation optical disc is approximately 170 nm. The line width of semiconductor process is reduced from several hundreds of nanometers to several tens of nanometers. Therefore, in order to fabricate extremely fine line width or recording pit, people have made continuous efforts to improve the method of lithography processing.
In a conventional lithography processing, organic material coated on a substrate is generally used as a photoresist layer, and the organic photoresist is exposed to blue light or ultraviolet light; next, the exposed region or the unexposed region is dissolved by using a characteristic that a developer has good dissolution selectivity to the exposed and unexposed organic photoresist, so as to fabricate fine pattern structure on the surface of the organic photoresist layer.
In the conventional process, a photo-sensitive organic material is used as the resist material, and mechanism utilizes the property of the material that photons with suitable wavelength will change chemical structure thereof, and such a change in the chemical structure makes the developer have obviously different solubility to the organic photoresist. However, even a small amount of photons can also cause a change in the chemical structure of the organic photoresist to some extent. Therefore, such method merely can fabricate line patterns or recording pits with similar size to the exposure light spot. Furthermore, the organic resist material is a polymer material, so after exposure and development, the edges of the patterns or the recording pits are likely to be rough, and fine line patterns or recording pits in the level of several nanometers are difficult to be fabricated.
Recently, in order to solve the problem that the conventional lithography process cannot achieve the fine line patterns or recording pits with the accuracy of several nanometers, a method of reducing the wavelength of the exposure light source has been set forth. However, the fabrication cost is increased significantly due to the problems such as short-wavelength laser is used and the optical elements of the exposure mechanism must be made of specific materials, and the problem that the edges of patterns or the recording pits become rough after exposure and development cannot be solved. Therefore, many more advanced techniques are applied in the lithography process, such as, ion-beam, electron-beam lithography technique. Though such techniques can meet the requirements of reaching the accuracy of several nanometers, the problems of slow process and high cost still exist.